This paper summarises the requirements of The Control of Vibration at Work Regulations 2005 (Regulations) and related HSE guidance, with respect to assessing daily exposure to Hand-Arm Vibration (HAV). 


Of greatest importance, due to some market confusion, is to highlight that the HSE’s response to Q7 of the Q&A on vibration exposure monitoring should not be considered in isolation. The response is only in reference to the measurement of vibration magnitude, which the HSE advise is not a legal requirement for employers when assessing HAV exposure risk if other suitable data is available. 


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An employer’s duties when assessing HAV exposure risk, are set out in the Regulations and related HSE guidance, excerpts from which are repeated below on the topic of assessing daily exposure to HAV.  
To summarise:
  • An employer who is liable to expose employees to vibration risk shall make a suitable and sufficient assessment of the risk. This is so vibration is either eliminated at source or, where not reasonably practicable, reduced to as low a level as is reasonably practicable (ref 1).
  • To assess exposure to HAV at or above an exposure action value or above an exposure limit value (ref 2), an evaluation of time “on tool” and hand transmitted vibration magnitude is required to calculate HAV daily exposure (ref 6).
  • Determination of vibration magnitude for an assessment of HAV exposure does NOT under the Regulation, require the measurement of a tool’s vibration in compliance to specific standards (ref 1, 5, 8 & 9).
  • The Regulation requires the employer to assess vibration risk by reference to relevant information on the probable magnitude of the vibration corresponding to the equipment used in the particular working conditions (ref 2, 4, 7).
  • Obtaining data for vibration magnitude in compliance with standards does NOT mean that it is suitable for a risk assessment unless it is also ensured that it is representative of the task being assessed (ref 3, 4, 10, 11).
  • The HSE FAQ guidance does NOT advise that wrist worn devices are unsuitable as an aid to allow an employer to assess risk to comply with Regulations but that they are unsuitable for on-tool measurements. 


How can HAVwear help address an employer’s obligations?

HAVwear calculates daily HAV exposure simultaneously by two methods of points calculation:
  1. Tool Exposure Points (TEP) – based on a static vibration magnitude programmed into a tool tag and duration of tool usage. If the static vibration magnitude is determined as representative for the tool usage as part of a risk assessment, TEP complies with the Regulations and HSE guidance. 
  2. Sensed Exposure Points (SEP) – based on a real-time determination of vibration magnitude during all use of the tool, which if assessed to be representative, will comply with the regulations and HSE guidance. An independent assessment by the IOM concluded that the HAVwear sensed vibration magnitude data would inform a suitable and sufficient risk assessment, carried out by an employer in accordance with Regulation 5. 
Concerns have been raised on the suitability of HAVwear due to the HSE FAQ on HAV monitoring question 7. Within the answer to Q7 the following statement is made “There is currently no wrist or glove mounted device which measures vibration suitable for use in a risk assessment”. However, Regulation 5(c) only requires measurement of vibration magnitude if necessary. On-tool measurement is required when there is no other source of determining the probable vibration magnitude for a tool (ref 8 & 9). In these circumstances it is appropriate to use both ISO5349 and ISO8041 in the hands of a skilled technician, eliminating the impact of the tool users influence in determining a vibration magnitude.  Practically and economically this would not be for the majority of tools or for every use of even the minority of tools due to the range of tool vibration behaviour as illustrated in Figure 13 and 14 from L140 (ref 12).
In the calculation of SEP daily HAV exposure, HAVwear determines probable vibration magnitude suitable for use in a risk assessment as it does not simply measure vibration magnitude on the tool user’s wrist. HAVwear uses algorithms to compensate for the transmissibility through the hand to the wrist and determines a vibration magnitude equivalent to the hand arm vibration transmitted to the tool user at the grip point. The Institute of Occupational Medicine year-long evaluation of HAVwear with extensive simultaneous tool testing to all appropriate standards found the HAVwear data to be comparable to the simultaneous measurements and potentially more suitable for a HAV exposure assessment as the HAVwear could capture the full use of the tool, rather than a point in time assessment. 
The Regulations state that vibration data used for the purposes of risk assessment must be credible and representative of the work being undertaken. Therefore, real time monitoring of vibration to assist in the selection of credible vibration magnitude data is supportive of these Regulations.  Both TEP and SEP data are acquired concurrently and can be compared to identify specific areas of concern and the drivers to static data not being representative such as tool wear or operator skill. An enhanced understanding of risk drivers will improve control measure refinement after initial risk assessments.
Put simply, HAVwear’s SEP data is suitable for daily risk assessment of HAV exposure which is representative of the risk being assessed allowing an employer to meet the requirements of Regulations. The HSE have not said a wrist worn device is not suitable as an aid to risk assessment in accordance with Regulation 5.
To explain the benefits of SEP consider Figure 1
A point-in-time measurement to ISO5349 and other standards can yield the results as illustrated in Section A, Figure 1. However, through the course of use of the tool the vibration magnitude can range as highlighted by the grey area in Figure 1.
A simultaneous HAVwear result for the point in time of section A in Figure 1, may have a greater range and may be slightly higher. However, as the tool is used through its differing purposes the HAVwear tracks the range of use. If you require to assess a task which covers Section B of the graphic which is more likely to be more relevant to the tool’s use - the static measurement in section A or the HAVwear determination in section B in Figure 1.
Figure 1
The Reactec HAVwear device was designed to determine vibration magnitude corresponding to the equipment used in the particular working conditions over a period of time.
HAVwear supports employers carrying out a risk assessment in accordance with Regulation 5 due to its ability to combine real-time information on the probable magnitude of the vibration corresponding to the equipment used in the particular working conditions. 




Sections from the Regulation 

5. Assessment of the risk to health created by vibration at the workplace 
(1) An employer who carries out work which is liable to expose any of his employees to risk from vibration shall make a suitable and sufficient assessment of the risk created by that work to the health and safety of those employees and the risk assessment shall identify the measures that need to be taken to meet the requirements of these Regulations. Ref 1
(2) In conducting the risk assessment, the employer shall assess daily exposure to vibration by means of;

(a) observation of specific working practices; 

(b) reference to relevant information on the probable magnitude of the vibration corresponding to the equipment used in the particular working conditions; and

(c) if necessary, measurement of the magnitude of vibration to which his employees are liable to be exposed,

And the employer shall assess whether any employees are likely to be exposed to vibration at or above an exposure action value or above an exposure limit value.Ref 2
6. Elimination or control of exposure to vibration at the workplace 
 (2) Where it is not reasonably practicable to eliminate risk at source …and an exposure action value is likely to be reached or exceeded, the employer shall reduce exposure to as low a level as is reasonably practicable by establishing and implementing a programme of organisational and technical measures which is appropriate to the activity. 



Sections from HSE Guidance

The Control of Vibration at Work Regulations 2005 Guidance on Regulations L140 
The Guidance is created by the HSE to provide clarification on the Regulation in Part 1 and HSE supporting information in Part 2. 
Part 1 - Legal duties of employers to control the risks to health and safety from hand-arm vibration
Suitable and sufficient risk assessment (Section 29)
Your exposure estimate will only be soundly based if it uses data which can be judged to be reasonably representative of your work process or, where you have made measurements, they have been done competently. Ref 3
Section 33 - “Relevant information on the probable magnitude of the vibration” 
To be relevant, the vibration information you use to do your vibration assessment needs to match as closely as possible the likely vibration performance of the equipment you plan to use in the way you plan to use it. There are several possible sources of suitable information on vibration levels. Ref 4
These include:
(a) vibration emission values declared in the equipment handbook; 
(b) additional information from the equipment supplier; 
(c) internet databases; 
(d) research organisations; vibration consultancies; 
(e) HSE’s website; 
(f) trade associations; 
(g) measurements made in your own workplace
Section 35 - “If necessary, measurement of the magnitude of vibration” 
This makes clear that measurement may sometimes be required, but that it may not be necessary if suitable vibration data are available. Ref 5
Section 38 - “Magnitude, type and duration of exposure”
The factors which govern a person’s daily vibration exposure are the magnitude (level) of vibration and the length of time the person is exposed to it. 



Part 2 - Assess vibration risks and develop an action plan for control 

What information is needed to assess daily exposure?
110. To estimate a worker’s daily vibration exposure you will need two pieces of information: 
  • the average magnitude (level) of the vibration at the surface in contact with the hand; 
  • and the daily exposure time (the time for which an employee’s hand is actually in contact with that vibration). Ref 6
What is the vibration magnitude?
111. Vibration magnitude is the level of vibration at the hand position on the tool, handle, workpiece etc. This is expressed as an acceleration value in metres per second squared (m/s2). 
112. The vibration magnitude for the use of a particular tool or a particular work process can be highly variable. It can be affected by the condition of the tool, the material being worked, the operator’s technique and how it was measured. It is often difficult to obtain a precise value that represents the vibration for a particular tool or task, however a precise value is not required so long as the value is representative of the work process and used in a way to achieve protection of most of those exposed, for example using vibration magnitudes in the upper part of the range. Ref 7
113. The Regulations require you to assess your employees’ daily exposures, so you can plan the necessary action to control the risk. It is not important to obtain a precise daily exposure (it will probably vary from day to day anyway). You just need enough information to establish whether it is likely that the exposure action or limit value will be exceeded. You may be able to do this without having to make vibration measurements in your workplace. Ref 8
Are vibration measurements required?
122. Although you are not automatically expected to make vibration measurements, the Vibration Regulations do require measurements where it is not otherwise possible to adequately assess the exposure and establish whether the exposure action or limit value is likely to be exceeded. Ref 9
123. You should remember, however, that hand-arm vibration magnitudes can be highly variable, and what is measured on one occasion is only a sample.Ref 10
124. Vibration measurement can be a difficult and complex task. You may choose to make measurements in-house or employ a specialist for this task. It is important that that whoever makes the measurements is competent
216. The examples below illustrate the limitations of manufacturers’ declared emission values where the vibration test code does not adequately reflect the vibration produced in real use of the tool.


Examples within L140

Interpretation of manufacturers’ declared vibration emission values
Vibration magnitudes on hand-held power tools can vary greatly from user to user and task to task, often by factors of 2:1 or 3:1 between the worst and best circumstances. Figure 13 shows ranges of vibration values measured on three tools performing their intended use in the workplace; these are shown by the vertical lines. The average (mean) of these measured values is shown by the mark to the right of the vertical line. The manufacturer’s declared emission value, measured using the harmonised test code, and supplied with the tool, is shown by the mark to the left of the vertical line.
For the impact drill the vibration found in ‘intended use’ varied between 5 and 17 m/s2 (with a mean of just over 10 m/s2). This was represented well by the declared emission value of about 12 m/s2. In this situation the declared emission value is suitable for estimating daily exposure.
For the chipping hammer the range in ‘intended’ use was from 10 to 26 m/s2 (mean approximately 16 m/s2). The standard emission test for the tool produced a value at the low end of this range, which nevertheless gives a clear indication that vibration emission magnitudes are high and will require management. However, this value would not be suitable to determine the daily operating time before exceeding the exposure action or limit value.Ref 11
For the rock drill the range in ‘intended’ use was 15 to 25 m/s2 with a mean of about 18 m/s2. The emission test produced a value of about 11 m/s2 which is below the range of levels measured during ‘intended use’ and again could not be used directly to show whether the exposure action or limit value is likely to be exceeded.
Despite the large variations found for each of the tools during ‘intended use’, and the failure of some of the standard tests to produce declared emission values within the range found during ‘intended use’, each of these tests produced a sufficiently high vibration emission value to demonstrate that daily exposure is likely to exceed the exposure action value (and perhaps the exposure limit value) and to warn of the likely presence of a vibration risk that will require management.
(The similarity of the levels found according to the standard emission tests for these three tools is coincidental.) 
The vibration data provided by suppliers can help to identify tools with relatively high or low vibration. Figure 14 shows data for two chipping hammers. Both hammers have a large range in their vibration emission depending on the task, etc., but it is clear both from the ‘intended use’ data and the supplier’s emission values that one of the hammers is a generally lower vibration tool than the other. However, although the emission value for hammer C helps to identify it as having the lower vibration, it fails to represent the higher vibration levels that will occur in real use and does not identify this tool’s potential to expose the operator above the action or limit value.
Ref 12



AMEY North Lanarkshire - Gerry Kennedy, Roads Manager

“Before the HAVmeter, we relied on manual input, with a guy basically using his memory at the end of the day for the time that he has spent using vibratory tools. With the HAVmeter, we have an accurate, user friendly piece of kit which allows us to manage HAV more easily. It really is a Health and Safety Management tool. We have been able to make major savings through cutting out administrative costs.”